package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.hmdp.dto.Result;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.UserHolder;
import jakarta.annotation.PostConstruct;
import jakarta.annotation.Resource;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.time.Duration;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.*;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
@Slf4j
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {
    @Resource
    private ISeckillVoucherService seckillVoucherService;
    @Resource
    private RedisIdWorker redisIdWorker;
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private RedissonClient redissonClient;
    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;
    static {//静态代码块里面进行初始化
        SECKILL_SCRIPT=new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));//设置脚本的本地位置为当前资源路径下的
        SECKILL_SCRIPT.setResultType(Long.class);
    }
    //阻塞队列
//    private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024*1024);
    //创建一个线程池
    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();//单线程
    @PostConstruct//使当前任务在这个类初始化完成之后就开始执行
    private void init(){
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }
    private IVoucherOrderService proxy;
    //创建一个线程任务
    private class VoucherOrderHandler implements Runnable {
        String queueName = "stream.orders";
        @Override
        public void run() {
            while (true) {
                try {
                    //1.获取消息队列中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STREAMS stream.orders
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create(queueName, ReadOffset.lastConsumed())
                    );
                    //2.判断消息获取是否成功
                    if (list == null || list.isEmpty()) {
                        //如果获取失败，说明没有消息。继续下一次循环
                        continue;
                    }
                    //3.解析消息中的订单信息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    //3.1如果获取成功，可以下单
                    handleVoucherOrder(voucherOrder);
                    //4ACK确认 SACK stream.order g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName,"g1",record.getId());
                } catch (Exception e) {
                    log.error("处理订单异常", e);
                    handlePendingList();
                }
            }
        }

        private void handlePendingList() {
            while (true) {
                try {
                    //1.获取pending-list中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 STREAMS stream.orders
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create(queueName, ReadOffset.from("0"))
                    );
                    //2.判断消息获取是否成功
                    if (list == null || list.isEmpty()) {
                        //如果获取失败，说明pending-list没有异常消息。结束循环
                        break;
                    }
                    //3.解析消息中的订单信息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    //3.1如果获取成功，可以下单
                    handleVoucherOrder(voucherOrder);
                    //4ACK确认 SACK stream.order g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName,"g1",record.getId());
                } catch (Exception e) {
                    log.error("处理pending-list订单异常", e);
                    try {
                        Thread.sleep(20);
                    } catch (InterruptedException ex) {
                        ex.printStackTrace();
                    }
                }
            }
        }
    }
    //创建一个线程任务
//    private class VoucherOrderHandler implements Runnable {
//
//        @Override
//        public void run() {
//            while (true) {
//                try {
//                    //获取阻塞队列中的订单信息
//                    VoucherOrder voucherOrder = orderTasks.take();
//                    //创建订单信息
//                    handleVoucherOrder(voucherOrder);
//                } catch (Exception e) {
//                    log.error("处理订单异常", e);
//                }
//            }
//        }
//    }

    private void handleVoucherOrder(VoucherOrder voucherOrder) {
        //1.获取用户id，此时是一个独立得我线程，没有办法从主线程中获取id
        Long userId = voucherOrder.getUserId();
        //2.创建锁对象
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        //3.获取锁
        boolean isLock = lock.tryLock();//默认是无参
        //4.判断是否获取锁成功
        if (!isLock) {
            //获取锁失败，返回错误或者重试
            log.error("不允许重复下单");
            return;
        }
        try {
            proxy.createVoucherOrder(voucherOrder);//省去了this，非代理对象
        } catch (IllegalStateException e) {
            throw new RuntimeException(e);
        } finally {
            //释放锁
            lock.unlock();
        }
    }

    /**
     * 优惠券秒杀下单
     */
    @Override
    public Result seckillVoucher(Long voucherId) {
        //获取用户
        Long userId = UserHolder.getUser().getId();
        //获取订单id
        long orderId = redisIdWorker.nextId("order");
        //1.执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(), userId.toString(),String.valueOf(orderId)
        );
        //2.判断结果是否为0
        int r = result.intValue();
        if (r != 0) {
            //2.1不为0，代表没有购买资格
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }
        //获取代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();//获得当前对象的代理对象交由spring容器来管理
        //4.返回订单id
        return Result.ok(orderId);
    }
    //异步解决秒杀下单的优化问题
//    @Override
//    public Result seckillVoucher(Long voucherId) {
//        //获取用户
//        Long userId = UserHolder.getUser().getId();
//        //1.执行lua脚本
//        Long result = stringRedisTemplate.execute(
//                SECKILL_SCRIPT,
//                Collections.emptyList(),
//                voucherId.toString(), userId.toString()
//        );
//        //2.判断结果是否为0
//        int r = result.intValue();
//        if (r != 0) {
//            //2.1不为0，代表没有购买资格
//            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
//        }
//        //2.2为0，有购买资格，把下单信息保存到阻塞队列
//        VoucherOrder voucherOrder = new VoucherOrder();
//        //2.3订单id
//        long orderId = redisIdWorker.nextId("order");
//        voucherOrder.setId(orderId);
//        //2.4用户id
//        voucherOrder.setUserId(userId);
//        //2.5代金券id
//        voucherOrder.setVoucherId(voucherId);
//        //2.6创建一个阻塞队列
//        orderTasks.add(voucherOrder);
//        //获取代理对象
//        proxy = (IVoucherOrderService) AopContext.currentProxy();//获得当前对象的代理对象交由spring容器来管理
//        //4.返回订单id
//        return Result.ok(0);
//    }
    /**
     * public Result seckillVoucher(Long voucherId) {
     * //1.查询优惠券
     * SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
     * //2.判断秒杀是否开始
     * if (voucher.getBeginTime().isBefore(LocalDateTime.now())) {
     * //尚未开始
     * return Result.fail("秒杀尚未开始!");
     * }
     * //3.判断秒杀是否已经结束
     * if (voucher.getEndTime().isAfter(LocalDateTime.now())) {
     * //已经结束
     * return Result.fail("秒杀已经结束!");
     * }
     * //4，判断库存是否充足
     * if (voucher.getStock())<1){
     * return Result.fail("库存不足!");
     * }
     * Long userId = UserHolder.getUser().getId();//每一次id的对象会变化
     * //        synchronized(userId.toString().intern()) {//是每一次的string的值都相同，缩小锁的确切范围来增加效率
     * //            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();//获得当前对象的代理对象交由spring容器来管理
     * //            //使其下方代码具有事务特性
     * //            return proxy.createVoucherOrder(voucherId);//省去了this，非代理对象
     * //        }//等事务提交完再来释放锁
     * //应用分布式锁解决下单冲突问题
     * //创建锁对象
     * //        SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
     * RLock lock = redissonClient.getLock("lock:order:" + userId);
     * //获取锁
     * <p>
     * / /        boolean isLock = lock.tryLock(1200);
     * boolean isLock = lock.tryLock();//默认是无参
     * //判断是否获取锁成功
     * if (!isLock) {
     * //获取锁失败，返回错误或者重试
     * return Result.fail("不允许重复下单!");
     * }
     * try {
     * IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();//获得当前对象的代理对象交由spring容器来管理
     * return proxy.createVoucherOrder(voucherId);//省去了this，非代理对象
     * } catch (IllegalStateException e) {
     * throw new RuntimeException(e);
     * }finally {
     * //释放锁
     * lock.unlock();
     * }
     * }
     **/
    @Transactional//俩张表的操作尽量加上事务注解
    public void createVoucherOrder(VoucherOrder voucherOrder) {//用悲观锁的方式解决查询问题
        //一人一单的判断
        Long userId = UserHolder.getUser().getId();//每一次id的对象会变化
        //查询订单,判断是否存在
        int count = Math.toIntExact(query().eq("user_id", userId).eq("voucher_id", voucherOrder).count());
        if (count > 0) {
            //该用户已经购买过
            log.error("用户已经购买过一次!");
//                return Result.fail("用户已经购买过一次!");
            return;
        }
        //5.扣减库存
        boolean success = seckillVoucherService.update()
                .setSql("stock=stock-1")
                .eq("voucher_id", voucherOrder)
                .gt("stock", 0)//用乐观锁解决资源冲突的问题，判断更新时和查询时是否处于同一种情况,用于更新数据的操作
                .update();
        if (!success) {
            log.error("库存不足!");
//                return Result.fail("库存不足!");
            return;
        }
        //6.创建订单
//            VoucherOrder voucherOrder = new VoucherOrder();
//            //6.1订单id
//            long orderId = redisIdWorker.nextId("order");
//            voucherOrder.setId(orderId);
//            //6.2用户id
//            voucherOrder.setUserId(userId);
//            //代金券id
//            voucherOrder.setVoucherId(voucherOrder);
        //创建订单
        save(voucherOrder);//将当前订单写入数据库
        //返回订单id
//            return Result.ok(orderId);
    }
}
